Maya's Ultimate Weapon - Persona 2: Innocent Sin Guides
The quest to get Maya's Ultimate Weapon can be started once you gain access to the Zodiac Temples towards the end of the game. In order to start this quest what you need to do is make Contact with demons during battle and form Pacts with them; once you've done this you'll need to ask them for information. The chances of you hearing this rumor are low but sometimes a demon will tell you about a legendary weapon being sold at Clair de Lune. This is the rumor needed that leads to Maya's Ultimate Weapon.
For those of you who don't understand the demon contact system in this game I recommend you check out my Contact With Demons Guide for more information. Knowing how this system works on a basic level is important for completing this Legendary Weapon quest.
In order to form a Pact with a demon you'll need to raise their Happy emotion 3 times, once a Pact is formed you'll have to raise Happy 3 times again during a subsequent battle with the same demon. You should check out my Demon Contact - Dialogue Choices Guide for more information about which dialogue choices raise Happy for each demon.
Once you've heard the rumor that a legendary weapon can be found at Clair de Lune you'll want to head to Clair de Lune to check it out. You can find the Clair de Lune shop in Aoba Way which is part of the Aoba Prefecture.
Inside of the Clair de Lune shop you'll want to speak with Garcon Soejima (pictured above); choose the 'Make small talk' dialogue option and Garcon will give you the rumor about the legendary gun that the store carries. Once you learn this rumor from Garcon you'll want to head to the Kuzunoha Detective Agency in the Hirasaka part of town and spread the rumor.
Return to Clair de Lune and there will be a scene with Garcon. During this scene in typical Persona 2 fashion you'll have to select the right dialogue choices otherwise you'll lock yourself out of buying this gun. When prompted with the first choice make sure you tell Maya to "Eat it." (I love how this sounds out of context)
For the second dialogue choice it doesn't matter what you select - I have tested it and both work. When the scene is finished talk with Garcon Soejima again and you'll be able to purchase the Legendary Gun from him for 500,000 Yen. That's all there is to obtaining Maya's Ultimate Weapon!
One of the unique things about the legendary weapons in Persona 2 is that you can make them stronger by learning rumors from demons and spreading them. After you obtain one of the legendary weapons in this game you'll start to see rumors appear in the 'give me information' dialogue about the weapon you obtained.
Each Legendary Weapon has a total of 6 rumors that you can learn and spread; all of these rumors cancel each other out so you can only spread one of them at a time. Out of all the rumors the best one is definitely "Legendary Weapon is Supreme", this will give your weapon a significant buff once you spread it.
Most of the other rumors will add elemental damage to your weapon and make it deal water, fire, earth or wind damage. Last but not least you have the rumor that your Legendary Weapon is inferior. As you can probably guess, the inferior rumor will lower the damage and quality of the weapon significantly.
1. Legendary Weapon is inferior
2. Legendary Weapon has the power of water
3. Legendary Weapon has the power of fire
4. Legendary Weapon has the power of earth
5. Legendary Weapon has the power of wind
6. Legendary Weapon is supreme
You may be thinking that this all sounds great but it comes with one catch that sounds worse than it really is. Demons can spread a rumor about your Legendary Weapon being inferior and make it a piece of crap... As I said though, this sounds a lot worse than it actually is because demons will very rarely spread this. The only way you can trigger a demon to spread this is if you cause them to be Scared 3 times during battle and they flee.
Even if you make a demon flee from battle it's still not a 100% chance that they'll spread this rumor about your weapon. If this does happen to you though all you need to do is spread one of the other 5 rumors about the weapon to cancel out the inferior one.